Airbag devices have become almost standard equipment in recent vehicles.
An airbag device is a safety device that operates during an emergency such as a vehicle collision, and inflates and deploys an airbag cushion (hereinafter simply referred to as “cushion”) with a gas pressure to receive and protect an occupant. Airbag devices come in various types in accordance with installation locations or applications. For example, in order to protect a driver from impact in the longitudinal (frontal impact) direction, a front airbag device is provided at the center of a steering wheel. In addition, in order to protect the occupant from impacts in the vehicle width direction (side impact) which are caused by a side collision or the like, a curtain airbag device is provided in the vicinity of a roof above a side window, and a side airbag device is provided in a side portion of a seat.
Various airbag devices are provided with a gas generating device called an inflator as a gas supply source. Various types of inflators also can be used depending on the type of the airbag and installation location thereof. For example, a disk-type (disk-like, or pancake) inflator is mainly used for a front airbag device, and a cylinder-type (cylinder-like) inflator is mainly used for a curtain airbag device and a side airbag device (see, for example, Japanese Patent Application Publication No. 2009-1057).